Presently, a double-gyroscopic mixer is available in the market, in which a paint can fixing device is obliquely provided. The double-gyroscopic mixer is specifically used for mixing paints in the paint can. By revolution (that is, the paint can is rotated about an axis, namely a revolution axis, which forms an angle with the geometrical axis of the paint can) and rotation (that is, the paint can is rotated about its own geometrical axis, namely a rotation axis), an ideal mixing effect may be achieved. At present, circular cans and square cans are commonly found. Accordingly, the paint can fixing device also includes circular paint can fixing devices and square paint can fixing devices applied to circular paint cans and square paint cans respectively. The present applicant filed a Chinese patent application No. 200920089170.6, titled “paint can-fixing device applicable to double-gyroscopic mixer” on Mar. 25, 2009, as shown in FIGS. 1 and 2. With the cooperation between a locking piece and a V-shaped groove of a guide rail, the upper pressing plate is slidable along the guide rail freely by grasping a pressing handle, and then, the secondary pressing device is rotated, so that the paint can between the upper pressing plate and the lower supporting plate can be clamped completely by the straight line stroke of the threads. At this moment, the machine can be actuated to mix the paints safely.
At present, such a paint can-fixing device of the double-gyroscopic mixer can effectively perform a mixing process for both the circular paint can and the square paint can having various dimensions. The friction cooperation between the locking piece and the V-shaped groove is safe and reliable, which effectively solves the problem of the falling of the paint can during the mixing process. Thus, the paint can-fixing device has a simple structure, and is safe and reliable. The prior technical solution includes two separate steps: pushing the upper pressing plate to slide along the guide rail so as to pre-tighten the paint can, and rotating the pressing spanner such that the paint can is clamped for the second time. Therefore, a technical solution having a simple structure and fewer operation steps would be desirable in the art.